1. Field of the Invention
The invention relates to an apparatus and method for regulating the temperature in an enclosed area. In one particular embodiment of the invention, the apparatus comprises a dry ice module that can be adapted or retrofitted to various items that need temperature regulating. The invention provides an apparatus for effectively utilizing dry ice as a temperature lowering means in any situation requiring the temperature to be controlled at a desired temperature. The dry ice module eliminates problems associated with the use of gel packs or wet ice (H2O) as the cooling vehicle when trying to maintain a consistently low temperature. By arranging various layers of insulation materials, such as THINSULATE®, TYVEK®, and a polyethylene foam enclosed in a reflective foil, such as the product sold under the name PRODEX® FfmF insulation by Insulation 4 Less, separately or in conjunction with the other, and the dry ice, the user of the dry ice module can effectively regulate the temperature of any items requiring controlled cooling for extended periods of time by controlling the rate at which dry ice sublimates.
Due to the wide range of temperature regulation that can be achieved using dry ice, one has greater flexibility over extended periods of time when using dry ice as a means of a cooling vehicle from above freezing (greater than 32 .degree. F.), down to sub-zero temperatures, and other temperatures in between. One embodiment of the invention includes an anti-freeze bag made out of breathable material, such as a spun bonded olefin, spun bonded-melt blown-spun bonded (SMS) polyethylene, or other materials with similar properties and characteristics available today or in the future, can assist in regulating the temperature. For example, different liquids freeze at varying temperatures and when kept in a cooling compartment that is just below 32 .degree. F., water tends to freeze first. As such, water bottles can be encapsulated in an anti-freeze bag allowing them to remain liquid, while other drinks that do not freeze at temperatures just below 32 .degree. F. remain in the liquid state as well.
Preferred embodiments of the invention include a vented module that houses dry ice while encapsulated in insulating and breathable materials, or a combination of such materials, allowing for the regulation of temperature to be regulated within a particular temperature range targeted for maintaining the particular items in a cooled but unfrozen state, while also allowing individuals to safely touch the dry ice module without getting injured.
Dry ice is made of carbon dioxide gas (CO2), the sublimation of which is a cooling vehicle in the present invention. Further, because of its molecular make-up CO2 is heavier than atmospheric air, and therefore falls to the lowest point possible. Accordingly, a dry ice module of the present invention is preferably positioned proximate the top of an enclosed body so that the CO2 gas falls downward. When the insulating and breathable materials comprising the dry ice module are assembled in a manner to achieve a desirable temperature, and the module is contained within an enclosed closed body, such as a cooler, the build up of pressure from the CO2 gas accumulated within the enclosed body is typically minimal, even when the lid is not opened for an extended period of time.
2. Description of the Related Art
Portable devices have been used for cooling food, beverages, medications and other items. In addition, portable coolers have been used in commercial applications, such as the shipment of perishable cargo, the transport of temperature sensitive medicines, laboratory samples, and transport of donor organs to medical facilities. Such coolers are typically non-electric, and configured to use water (H2O) in a frozen solid state (“wet ice”). However, to ensure adequate temperature regulations, one must repeatedly drain a large majority of the surplus water created from the melted wet ice, and add a fresh supply of wet ice. This process is time consuming, messy, does not provide a uniform temperature over an extended period of time, has the potential to soak and ruin inadequately protected items that are adversely affected by water, and requires a renewable source of wet ice. Although wet ice is widely available in gas stations, motels, convenience stores, restaurants, and similar commercial establishments, when temperatures surrounding the temperature sensitive materials are significantly elevated, additional supplies of wet ice may be needed more than once a day to maintain the temperature below a desired level for optimal consumption and/or spoilage prevention.
Alternatively, gel packs and other refreezable pre-packaged products are available for use instead of wet ice, or in combination therewith. However, to be reused, they have the disadvantage of requiring refreezing in something such as a household freezer, which is not typically available during travel away from home, and other environments in which the cooler is to be used. In addition, the amount of cooling time provided depends upon their size, and they are rigid which takes up valuable space that otherwise could be devoted to items requiring cooling. Further, although the gel packs and other refreezable pre-packaged products are commonly available and eliminate the messiness associated with wet ice, they are not typically large enough to provide temperature regulation for periods longer than are possible with wet ice. It would therefore be useful to have a method of temperature regulation that can maintain lowered temperatures for extended periods of time without replenishment, maintain a temperature range to protect things from spoilage, offer an alternative to current cooling methods used by individuals wearing protective body suits, and provide temperature regulation without the mess associated with wet ice and other liquid media, while also providing the ability to cool or freeze contents at a level far below conventional cooling means.